Connection for power amplifiers



Jan. 19, 1932. c. F. GOUDY CONRECTION FOR POWER AMPLIFIERS Filed June22, 1926 ATTCIRN EY Patented Jan. 19, 1932 UNITED STATES PATENT oFFIcECARL r. sonny, or r' IUsHmG, NEW YORK, AssIeNoR 'ro PAcEN'r ELECTRICCOMPANY,

me, on NEW YORK, N. Y., A CORPORATION OF NEW YORK the power amplifier,

CONNECTION FOR POWER AMPLIFIERS Application filed June 22,

power amplifierembodying a stage of audio frequency amplification, ithasusually been found advisable toeliminate theaudio frequency stages or atleast the last audio-frequency stage in the receiving set. WVhere thereceiving set is equipped with jacks in the detector or first audiostages, this is a simple matter. A great many sets,.however, are notequipped with jacks or other outlets atthese points and the presentinvention aims to provide simple and readily adaptable means by whichthe power amplifier may be connected in with the 'detector or firstaudio stage in those receiving'sets which are not equipped for such aconnectiom More particularly, the invention is concerned withreceivingsets equipped with the flat top style of sockets designed for thesocalled U. X3? tubes now largely used.

Special objects, therefore are to provide an adapter which can beplugged into a tube socket and which will provide an outlet from theplateor output side of the tube directly to the power amplifier, thusbypassing the following stages in the set.

A special feature of the invention is the construction of the device inthe nature of an adaptergplug having contact sockets at its upper sideto'receive the usual four prongs of the tube and having at its underside only three of the usual four prongs; these designed to fit into.the socket and the fourth or plate prong being left off and in itsstead a wire connection being provided for carrying off the outputof thetube directly to Various other novel features of the invention willappear as the specification proceeds. V f I The drawings accompanyingandforming part of this specification illustrates one practicalembodimentof the invention and it should 'be understood that the structure may bemodified without departure from the true spirit and scope of theinvention as hereinafter definedand broadly claimed.

Figure 1 'is aschematic representation of 1926. Serial No. 117,656.

a typicalU. X. socket five tube receiving set llustratlng the inventionin usefor by-pass- 'mg the last audio-frequency stage and for directlyto the power amplifier.

Figure 2 is a cross sectional view of the deviceas plugged into the tubesocket and same.

Figure 5 is a side elevation of the adapter.

Figure 6 is a plan view of the tube socket to which the connection isapplied.

The radio receiving set indicated generally at 7 in Figure 1 is of ausual type embodying two radio frequency tubes 8, 9, a detector tube 10and first and second audiofrequency tubes 11, 12. These tubes are allshown mounted in tube sockets 13.

The sockets illustrated are of special design in that they haveapproximately circular cap pieces 14: yieldingly supported on the bases15 by means of combined contact and terminal springs 16, the cap pieceshaving two large and two small openings 17, 18, respectively, to receivethe corresponding large and small prongs of the tube.

The toy-passing adapter is designedto plug into the socket after themanner of a tube and is equipped with socket contacts to itself receivethe tube.

In the illustration the body of the adapter is a fiat insulating member19,like-the cap piece of the socket, preferably the same as that pieceso that the two may be used interchangeably for tube sockets or withthis spe- In similarfashion, the lower plate 23' of carrying the outputof the first'audio stage the plug carries the four contact springs 24,25, 26, 27 corresponding in position and location to the socket contactsand extending upwardly into the prong sockets 28, 29, 30, 31 5respectively in the top of the plug. The first two of these sockets areof the larger size corresponding to sockets 17 in the tube socket andthe second pair are smaller in size corresponding to the smaller sockets18. The adapter is thus equipped to receive the prongs of the tube inthe same manner as the tube socket.

Three of the adapter springs, namely, those numbered 24, 25 and 26 areriveted or otherwise secured to prongs 32, 33 and 34, projectingdownwardly from the base plate 23 similar to the corresponding threeprongs of a tube. The fourth contact, 27, which becomes the output orplate terminal when the tube is inserted in the'base of the adapter, has

no prong extension and instead, a wire extension 35 is secured to thefoot of the same at 36 above the base plate, which wire is shown aspassed upwardly and out through a guide opening 37 extending upwardlyand out through the side of the adapter. At its free end the extensionwire 35 is preferably equipped with a terminal 351 having a socket toreceive a telephone cord tip or wire end held in place by a set screw38.

The receiving set shown is illustrated as having an output jack 39 whichordinarily would have one terminal connected with the positive side ofthe high voltage or B battery of theset. Therefore, it is possible touse this one terminal of the jack in making connection with the poweramplifier. A telephone plug 40 is therefore shown inserted in this jack,having one side 41 of a telephone cord 42 connected thereto and theother terminal 43 of'the other side of this cord is shown engaged in thesocket of the extension'wire terminal 351. The cord, 42, thus becomes aconnection for carrying'the output of the receiving set to the poweramplifier, saidcord being illustrated as having at its other end, atelephone plug terminal 43, entered in the input side of the poweramplifier, indicated at 44. The output from this amplifier is shownconnected by asuitable cord circuit 45 with the speaker 46. This poweramplifier may be of anyusual or special type and is indicated asembodying a rectifier tube 47 and an amplifier tube 48, saidtubesreceiving energy from a-cord circuit 49 designed to be plugged in on theordinary house lighting system. I

To use the invention'itwill be seen that it 'is only necessary to removethe detector or the first audio tube, depending upon whether both audiostages or only the last'audio stages are or is to be eliminated and toinsert in the vacated socket, the three prong-ed adapter, after whichthe tube is inserted in "the adapter and the connection from the adapteris engaged with the free terminal of the telephone cord.

The adapter should be inserted in the socket with its prongs positionedto correspond with the prongs of the tube for which it has beensubstitutedso that whenthe tube is inserted into it, the properconnections will result. Accordingly, the adapter is preferably markedwith an arrow 50 or the like just as is the socket so that when the plugis i11- serted in the socket with the arrows in alignment, the outputprong of the tube will engage with the extension cord contact of theadapter when the tube is inserted.

The adapter structure is simple and durable and relatively inexpensive,particularly so because of the fact that duplicate parts may be used inadapters and sockets. -The device furthermore occupies butsmall spaceand the extensionwire is small so that it ma '85 be brought out over thetop or at the bac of the usual front panel.

What is claimed is:

1. In a device of the character disclosed, a Hat plug base having prongpassages through 00 the top thereof, a flat insulating plate spacedbelow and secured to the under side of said base, .contact springsprojecting upwardly from said plate into the prong sockets, an extensionwire connected with one of said contact springs and prongs correspondingto tube prongs projecting from the plate and connected with the othercontact springs.

2. In a device of the character disclosed,

a plug base having prong passages in the to no thereof, an insulatingplate at the under si of said base, contact springs projecting u wardlyfrom said plate into the prong soc ets, an extension wire connected withone of said contact springs and prongs correspond- I05 ing to tubeprongs projecting from the plate andconnected with the other contactsprings, said insulating plate being spaced below the plug member by aninsulating stud, the extension wire being located in said space and theplug member having an opening extending from underneath out through theside of the same for said extension wire.

3. An adapter of the character disclosed, comprising a plate ofinsulating material, 116 prongs corresponding to radio tube prongsprojecting downwardly from said plate, a flat insulating cap havingprong passages therethrough, means securing said cap memher in spacedrelation above said insulating 120 plate, spring contacts carried bysaid insulating plate and having their upper ends projecting upwardlyinto the prong passa es in the cap member, electrical connections atweensome of said contacts and pron s, and 126 a wire connected with andextending o from a contact insulated from all the prongs.

In witness whereof, I have hereunto set my hand this 18th day of June,1926.

CARL F. GOUDY. T80

